"I can confirm that the shooter is dead," Deputy Chief Kris Arneson told reporters. "And he died by a gunshot wound -- self-inflicted."

Police did not immediately give a motive for the shooting.

Raymond Thomas "R.T." Rybak Jr. said that he visited the business about a month ago and that it was rapidly expanding around the world "because they have such cutting-edge technologies."

Accent Signage Systems specializes in interior signs that help the visually impaired, CNN affiliate KARE reported. The company holds a patent for technology that imprints Braille on things like hotel room numbers and restroom signs.

According to the company's Facebook page, Accent started as a part-time engraving business out of company president Reuven Rahamim's basement in 1984, KARE reported.

Accent now employs about 30 people and earns $5 million to $10 million each year, the station reported.

A neighbor who lives close to the business told KARE that an Accent employee hid in her house to escape the shooting.

"He was visibly fearful," Barb Gasterland said. "He came running up the side of the road and asked for the phone because he was running from the shooter."

Gasterland told KARE that the employee saw his boss and best friend get shot, along with two others.

In a statement, Minnesota Gov. Mark Dayton said he deplored the "senseless" shooting. "There is no place for it anywhere in Minnesota," he said.